0700-search-in-a-binary-search-tree.js

/**
 * 700. Search in a Binary Search Tree
 * https://leetcode.com/problems/search-in-a-binary-search-tree/
 * Difficulty: Easy
 *
 * You are given the root of a binary search tree (BST) and an integer val.
 *
 * Find the node in the BST that the node's value equals val and return the
 * subtree rooted with that node. If such a node does not exist, return null.
 */

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @param {number} val
 * @return {TreeNode}
 */
var searchBST = function(root, val) {
  while (root) {
    if (root.val === val) {
      return root;
    }
    root = root.val > val ? root.left : root.right;
  }

  return null;
};